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authorLiu Bo <bo.li.liu@oracle.com>2015-07-28 18:03:30 +0800
committerChris Mason <clm@fb.com>2015-08-09 07:33:50 -0700
commitacdf898de8903f50bb10bbce4b774432bcd63c85 (patch)
tree79d2c35cc5ec383bb0edff3ec5c116b4c902622b /fs/btrfs
parent166f66d0bc94a14ec4bc6ee6ab079532df4a8d9e (diff)
Btrfs: fix warning in backref walking
When we do backref walking, we search firstly in queued delayed refs and then the on-disk backrefs, but we parse differently for shared references, for delayed refs we also add 'ref->root' while for on-disk backrefs we don't, this can prevent us from merging refs indexed by the same bytenr and cause find_parent_nodes() to throw a warning at 'WARN_ON(ref->count < 0)', for example, when we have a shared data extent with 'ref_cnt=1' and a delayed shared data with a BTRFS_DROP_DELAYED_REF, that happens. For shared references, no matter if it's delayed or on-disk, ref->root is not at all used, instead it's ref->parent that really matters, so this has delayed refs handled as the same way as on-disk refs. Signed-off-by: Liu Bo <bo.li.liu@oracle.com> Signed-off-by: Chris Mason <clm@fb.com>
Diffstat (limited to 'fs/btrfs')
-rw-r--r--fs/btrfs/backref.c8
1 files changed, 2 insertions, 6 deletions
diff --git a/fs/btrfs/backref.c b/fs/btrfs/backref.c
index a0ca5757a3ff..ecbc63d3143e 100644
--- a/fs/btrfs/backref.c
+++ b/fs/btrfs/backref.c
@@ -655,7 +655,7 @@ static int __add_delayed_refs(struct btrfs_delayed_ref_head *head, u64 seq,
struct btrfs_delayed_tree_ref *ref;
ref = btrfs_delayed_node_to_tree_ref(node);
- ret = __add_prelim_ref(prefs, ref->root, NULL,
+ ret = __add_prelim_ref(prefs, 0, NULL,
ref->level + 1, ref->parent,
node->bytenr,
node->ref_mod * sgn, GFP_ATOMIC);
@@ -687,11 +687,7 @@ static int __add_delayed_refs(struct btrfs_delayed_ref_head *head, u64 seq,
struct btrfs_delayed_data_ref *ref;
ref = btrfs_delayed_node_to_data_ref(node);
-
- key.objectid = ref->objectid;
- key.type = BTRFS_EXTENT_DATA_KEY;
- key.offset = ref->offset;
- ret = __add_prelim_ref(prefs, ref->root, &key, 0,
+ ret = __add_prelim_ref(prefs, 0, NULL, 0,
ref->parent, node->bytenr,
node->ref_mod * sgn, GFP_ATOMIC);
break;